Thermoplastic resins exhibit good properties, such as low specific gravity, good moldability, and good impact resistance, as compared with glass or metal, and are useful for housings of electrical/electronic products, automotive interior/exterior materials, and exterior materials for buildings. Particularly, with the trend toward larger and lighter electrical/electronic products, plastic products produced from thermoplastic resins are quickly replacing existing glass and metal-based products.
Particularly, it is known in the art that a blend of a polyester resin and a polycarbonate resin exhibits both properties of the polyester resin such as high mechanical strength and good moldability and properties of the polycarbonate resin such as good thermal resistance, impact stability and dimensional stability.
In order to satisfy the recent trend of increasing the size of components, there is increasing demand for materials having high flowability. When a polycarbonate resin having a low weight average molecular weight is used in order to increase flowability of the blend of the polycarbonate resin and the polyester resin, there is a problem of deterioration in thermal resistance and mechanical properties such as impact resistance. Moreover, when the amount of the polyester resin is increased in order to improve flowability of the blend, there is a problem of deterioration in extrusion stability due to difference in viscosity between the polyester resin and the polycarbonate resin.